1. Field of the Invention
The present invention relates to a floating type magnetic head device for use in a hard disk apparatus or the like. In particular, the invention relates to a magnetic head in which a slider and a flexure for supporting the slider are bonded together with an adhesive.
2. Description of the Related Art
FIG. 3 is a partial side view of a known magnetic head device for use in a hard disk apparatus.
The magnetic head device includes a slider 1 and a support 2 for supporting the slider 1.
The slider 1 is composed of a ceramic material or the like. A thin-film element 4 is provided on the trailing end B, and the thin-film element 4 includes an MR head (read head) for reading magnetic signals by detecting a leakage magnetic field from a recording medium such as a hard disk, using a magnetoresistance effect, and an inductive head (write head) in which a coil and so on are formed by patterning.
The support 2 includes a load beam 5 and a flexure 6.
The load beam 5 is composed of a leaf spring material such as stainless steel, and has a bent section 5a having rigidity on each side of the front portion. A predetermined elastic force can be displayed at the base end of the load beam 5 in which the bent section 5a is not formed.
A spherical pivot 7 which protrudes downward in the drawing is formed in the front portion of the load beam 5, and the slider 1 abuts against the pivot 7 with the flexure 6 therebetween.
The flexure 6 is composed of a leaf spring such as stainless steel. The flexure 6 includes a fixed section 6a and a tongue 6b, and a step 6c connects the fixed section 6a to the tongue 6b.
As shown in FIG. 3, to the lower surface of the tongue 6b, the slider 1 is bonded with a resin adhesive 20. An example of the resin adhesive 20 is a thermosetting epoxy resin adhesive.
A conductive pattern (not shown in the drawing) is provided on the reverse side of the tongue 6b, and an electrode terminal section (not shown in the drawing) formed of a thin film extracted from the thin-film element 4 is provided on the trailing end B of the slider 1. At the junction between the conductive pattern and the electrode terminal section, a joint 9 is formed by ball bonding using gold (Au) or the like. The joint 9 is covered with a reinforcing resin film 10 for protection.
A fillet conductive resin film 21 is formed between the leading end A of the slider 1 and the tongue 6b. The conductive resin film 21 is provided to secure electrical connection between the slider 1 and the flexure 6 and to dissipate static electricity to the support 2.
The upper surface of the tongue 6b abuts against the pivot 7 formed on the load beam 5, and the slider 1 bonded to the lower surface of the tongue 6b can change the attitude freely, by means of elasticity of the tongue 6b, with the apex of the pivot 7 serving as a fulcrum.
The slider 1 of the magnetic head device is applied force with the elastic force of the base end of the load beam 5 in the direction of the disk D. The magnetic head device is used for a so-called "CSS" (Contact Start Stop) type hard disk apparatus or the like, and when the disk D stops, an air bearing surface (flying surface) 1a comes into contact with the recording surface of the disk D. When the disk D starts, an airflow occurs between the slider 1 and the surface of the disk D along the disk movement, and the slider 1 is lifted by a short spacing .delta.2 from the surface of the disk D because of a lifting force caused by the airflow.
When the slider 1 is lifted, as shown in FIG. 3, the leading end A of the slider 1 is lifted higher above the disk D than the trailing end B. While maintaining the lifting attitude, magnetic signals from the disk are detected by the MR head of the thin-film element 4, or the magnetic signals are written by the inductive head.
In the conventional magnetic head device, however, the flatness or crown height of the air bearing surface 1a of the slider 1 may easily change, resulting in extreme difficulty in setting the spacing .delta.2 at a given amount.
The flatness or crown height of the air bearing surface 1a of the slider 1 easily changes because a rigid adhesive such as a thermosetting epoxy resin adhesive is conventionally used as the resin adhesive 20 for bonding the upper surface of the slider 1 and the lower surface of the tongue 6b of the flexure 6 together.
As shown in FIG. 3, the trailing end B of the slider 1 is rigidly bonded to the tongue 6b of the flexure 6 by the joint 9 formed by ball bonding.
Additionally, since the slider 1 has a coefficient of thermal expansion which is different from that of the flexure 6, if the resin adhesive 20 bonding the upper surface of the slider 1 and the lower surface of the tongue 6b together is rigid, thermal stress owing to the difference in coefficient of thermal expansion between the tongue 6 and the slider 1 may affect the slider 1 with the resin adhesive 20 therebetween, resulting in adhesive deformation with respect to the slider 1.
Generally, since the flexure 6 has a larger coefficient of thermal expansion in comparison with the slider 1, for example, in the low temperature region, the air bearing surface 1a of the slider 1 is deformed to be convex in relation to the disk D, and thus a spacing loss increases, resulting in a decrease in output.
In the high temperature region, the air bearing surface 1a of the slider 1 is deformed to be concave in relation to the disk D, and thus it is highly possible that the trailing end B of the slider 1 collides with the surface of the disk D, and the minimum flying height (spacing amount) cannot be guaranteed.
Also, as shown in FIG. 3, when the conductive resin film 21 is provided between the leading end A of the slider 1 and the tongue 6b of the flexure 6, if the conductive resin film 21 is rigid the same as the resin adhesive 20, both the trailing end B and the leading end A of the slider 1 are rigidly bonded, resulting in larger adhesive deformation with respect to the slider 1 owing to thermal stress.